Stretcher device for articles under manufacture on double cylinder circular knitting machines

ABSTRACT

A stretcher device for articles under manufacture on double cylinder circular knitting machines has a first hydraulic piston cylinder unit fixed coaxially above the needle cylinder and a first pair of vertical rods supported on the stem of the pistoncylinder unit. The stretcher devices also comprises a second hydraulic piston-cylinder unit co-axial with the first one. The piston of the latter piston-cylinder unit is formed with cavities for the slidable passage of the first pair of rods. A second pair of rods is arranged to pass into corresponding passages formed in a body rigid with the needle cylinder. Engagement means for the articles, under manufacture are supported by the two pair of rods and arranged to be alternately moved in an upward and downward direction by the two piston-cylinder units.

United States Patent Lonati 1 Mar. 19, 1974 STRETCHER DEVICE FOR ARTICLES 713,251 9/1966 1ta1y...-.... 66/149 R UNDER MANUFACTURE ON DOUBLE 8/ 3 8 u 66/ 1 4 reat ritain.... 6 O

CYLINDER CIRCULAR KNITTING 649,846 9/1937 Germany 66/150 MACHINES Inventor: Francesco Lonati, Via S. P010 11,

Brescia, Italy 25100 Filed: Apr. 24, 1972 App]. No.: 271,263

Related US. Application Data Continuation-impart of Ser. No. 188,693. Oct. 12, 1971.

Foreign Application Priority Data Oct. 7, 1971 ltaly ..29606/71 U.S. CL. 66/149 R, 66/147 Int. Cl. D04b 15/88, D041) 27/34 Field of Search 66/149 R, 149 S, 150, 153,

References Cited UNITED STATES PATENTS 5/1966 Dodds B131 66/149 R 2/1967 Rossler 11/1954 12/1968 DOCekal et al 66/147 FOREIGN PATENTS OR APPLICATIONS 11/1966 Italy 66/149 R Primary Examiner-James Kee Chi V Attorney, Agent, or Firm--Dr. G. Modiano; Dr. A. Josif [5 7] ABSTRACT A stretcher device for articles under manufacture on double cylinder circular knitting machines has a first hydraulic piston cylinder unit fixed coaxially above the needle cylinder and a first pair of vertical rods supported on the stem of the piston-cylinder unit. The stretcher devices also comprises a second hydraulic piston-cylinder unit co-axial with the first one. The piston of the latter piston-cylinder unit is formed with cavities for the slidable passage of the first pair of rods. A second pair of rods is arranged to pass into corresponding passages formed in a body rigid with 1 the needle cylinder. Engagement: means for the articles, under manufacture are supported by the two pair of rods and arranged to be alternately moved in an upward and downward direction by the two piston cylinder units.

9 Claims, 9 Drawing Figures PAIENTEDHARW 1914- 3.797280 SHEEI '4 [If 7 /t I a ZOLL; 9 v /3 PAIENTEU MAR l 9 i974 SHEET 5 1F 7 PAIENTEDMAR 1 9 m4 SHEET 6 [IF 7 CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part application of my prior copending U.S. application, Ser. No. 188,693 filed Oct. 12, 1971.

BACKGROUND OF THE INVENTION The present invention relates to a stretcher device for articles under manufacture on double cylinder knitting machines.

A device comprising a vertical hydraulic cylinder fixed above the needle cylinders, in which slides a piston to which a pair of substantially vertical rods located a short distance one from the other and rotatable about the axis of the piston are attached, these rods passing through corresponding passages formed in a body rigid with said needle cylinders and supporting at their lower ends the means which engage with the articles under manufacture, is disclosed in my parent application.

This device has been shown in practice to be most advantageous, but is limited however by the length of said cylinder. in fact the useful drawing stroke for the products under manufacture corresponds substantially to the length of the cylinder, because of which said device is suitable only for the weaving of socks and stockings in which the leg and top band are shorter than the aforesaid useful drawing stroke.

For reasons of size it is not possible to increase the length of said cylinder beyond a certain limit; because of which in practice it is not possible to manufacture stockings of appreciable length, such as stocking tights.

SUMMARY OF THE INVENTION The main object of the present invention is to obviate the aforementioned disadvantages by providing a stretcher device adapted for the manufacture on double cylinder circular machines of articles of any length, and in particular of stocking tights and the like.

Another important object of the invention is to provide a device of rational conception, of reliable and regular operation, and which is easily applicable to double cylinder circular machines of any type.

These and still further objects are attained by the stretcher device for articles under manufacture on double cylinder circular knitting machines, according to the invention, including a first substantially vertical hydraulic cylinder fixed coaxially above the needle cylinders, a first piston slidingly mounted in said first hydraulic cylinder and rotatably supporting a first pair of vertical rods passing through corresponding passages formed in a body rigid with said needle cylinders and supporting at their lower ends first means of engagement with the articles under manufacture, said device being characterised in that it comprises a secondhydraulic cylinder preferably coaxial with the first, a second piston slidably mounted in said second cylinder and provided with cavities for the slidable passage of said first pair of rods, a second pair of rods rotatably attached to said second piston and located in a substantially vertical direction a short distance one from the other, and passing into corresponding passages formed in said body rigid with the needle cylinders and sup-.

2 porting at their lower ends second means of engagement with said articles under manufacture, said first and second hydraulic cylinders being operable independently and at different times for moving in an upward or downward direction said first and second means of engagement with the articles under manufacture alternately.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics and advantages of the invention will be more evident from the detailed description of a preferred but not exclusive embodiment of a pusher device, according to the invention, for double cylinder circular machines for the manufacture of stockings, illustrated by way of example with reference to the accompanying drawing in which:

FIGS. 1, 2,3 and 4 are diagrammatic axial sections of the device according to the invention in various op erating positions respectively;

FIGS. 5a, 5b and 5c are, in order of succession, complemental Figures of an axial section on an enlarged scale of the main part of the device according to the invention; for the sake of clarity in the complemental Figures an end area of each figure is shown also in the next complemental Figure.

FIG. 6 is a partial cross-section along the line Vl--Vl of FIG. 5;

FIG. 7 is a partial cross-section along the line VII- -VII of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to these figures, the device according to the invention comprises a main assembly 1 substantially similar to that provided in said parent application and an auxiliary assembly 2 mounted coaxially.

More precisely said main assembly 1 comprises a cylinder 3 of appreciable length fixed coaxially above the auxiliary assembly 2 which, in its turn, is mounted on the fixed structure, coaxially with the needle cylinders 4 and 5. A piston 6 is slidingly mounted tight in the cylinder 3 and is lowerly attached to two rods 7disposed vertically a short distance one from the other and symmetrically with respect to the axis of the cylinder 3. The connection is made by fixing the upper ends of the rods 7. to a plate 8 and this latter to a shaft rotatable in a supporting ball bearing 9 mounted on the piston 6.

At the lower end the rods 7 support a substantially truncated conical body 10 provided with a plurality of projections 10a placed at regular intervals which, in their turn, are provided with points 11 which engage with the articles under manufacture. The rods 7 pass slidingly into corresponding holes formed in a substantially cylindrical body 12 rotatably mounted at the base of the cylinder 3 by way of a ball bearing 13. The body 12 is provided with seal gaskets. The cylindrical chamber created in the cylinder 3 above the body 12 is fed with compressed fluid by way of a duct 14 comprising a valve 15.

Weights 16 may be inserted above the piston 6 in order to increase the tension.

So that the truncated conical body 10 can rotate together wth the needle cylinders 4 and 5, the rods 7 are made to pass slidingly also through holes in a disc 17 which is fixed by screws 17a to the cylinder 4.

The auxiliary assembly 2 comprises a cylinder 18 to the inside of which a tubular body 19 is coaxially fixed so as to form a chamber 20 of annular conformation within which a piston 21 of hollow centre can slide vertically. The lower end of the piston 21 is provided with lipped gaskets 22 which ensure tightness as it slides in the annular chamber 20, and at the upper end the piston 21 is provided with a disc 23 rotatably mounted by way of a ball bearing 24 and provided with holes for passage of the rods 7. The upper threaded ends of two further vertical rods 25 pass through the same disc 23 and are secured thereto by means of nuts, as visible in FIG. 50. These rods 25 are shorter than rods 7 and are disposed a short distance one from the other, symmetrically with respect to the axes of the needle cylinders 4 and 5, and turned through 90 with respect to the rods 7. Said disc 23 is fixed to the piston 21 by means of screws and washers 26. With this arrangement the disc 23, together with the rods 25 and 7, can rotate around the axis of the piston 21.

At the lower ends the rods 25 support an inverted cup 27 which is secured thereto by means of nuts screwed on the'threaded ends of these rods which pass through the cup 27, as visible in FIG. a. The cup 27 is provided laterally over nearly the whole of its height with a plurality of vertical notches 27a in which vertical strips 27b are located at regular intervals for insertion between the lateral projections a of the truncated conical body 10 (FIG. 7). Said strips 27b are provided with points 28 which engage with the articles under manufacture. The rods 7 slide through the bottom of the body 27 through corresponding holes, and the rods 25, in a similar manner to the rods 7, pass into corresponding holes provided in the plate 17 (FIG. 6), disposed crosswise to the former.

In this manner the rotation of the needle cylinders 4 and 5 causes the pairs of rods 7 and 25 to rotate by means of the plate 17, and hence also the points 11 and 28 carried by the bodies 10 and 27 respectively.

The piston 21 falls by gravity, and its action can be accelerated by adding weights 29 to it. It is raised however by feeding compressed fluid into the lower end of the chamber 20, through a duct 30 provided with a valve 31.

Inside the lower needle cylinder 5 and rigid with it there is a tube 32 for guiding the article 33 under manufacture, and which is connected at the lower end to a duct 32a connected to the discharge port 34, which, in its turn, is in communication with an aspirator 35 (the system for discharging the manufactured products from the circular machine is of conventional type).

Considering the manufacture ofa stocking, at the beginning of manufacture of its edge 33a the arrangement is that shown in FIG. 1, i.e., the pistons 6 and 21 are kept raised by feeding compressed fluid through the ducts 14 and 30, with the result that cup 27 and truncated conical body 10, and hence the points 11 and 28, are also raised. The truncated conical body 10 is inserted for a short distance into the cup 27, as clearly shown in FIG. 5.

After the circular machine has formed the edge 33a, or a portion of it, the valve is operated so as to connect it to discharge, so that the piston 6 and the members 7 and 10 supported by it fall under the action of their own weight. In this manner the truncated conical body 10 falls into the needle cylinder 5 (FIG. 2) until the corresponding points 11 engage with the fabric under manufacture. The fabric is pushed downwards in this manner as it is produced, so remaining under suitable tension, the truncated conical body 10 rotating together with the needle cylinders 4 and 5.

During this stage the compressed fluid is continuously fed into the annular chamber 20 through the duct 30, so as to keep the piston 21 raised and with it the cup 27 carrying the points 28.

The circular machine continues to produce fabric as the mobile assembly 6, 7 and 10 descends under its own weight maintaining the article 33 under tension. Before it reaches the end of its stroke i.e. before the truncated conical body 10 reaches its lowest position, the valve 31 (FIG. 3) is put into the discharge position so that the mobile assembly formed by the piston 21, rods 25 and cup 27 descends under its own weight until the points 28 engage with the article under manufacture. The suction fan 35 is simultaneously operated, and this condition is maintained for a number of knitting rotations.

Immediately afterwards compressed fluid is fed into the cylinder 3 (FIG. 3) so that while the body 27 engages the article 33 with its points 28 and pushes it downwards with suitable tension, the truncated conical body 10 is moved upwards by the movements of the piston 6.

By maintaining suction in the tube 32 with the suction fan 35, the stocking 33 is prevented from being dragged upwards by the body 10.

The mobile assembly 6-7-10 is returned to its initial maximum raised position (FIG. 4) whereas the other mobile assembly 21-25-27 continues to descend by gravity so maintaining the stocking under manufacture in tension.

However immediately after the assembly 6-7-10 has reached its maximum raised position, the valve 15 is connected to discharge so that said assembly commences to descend under its own weight until it again engages the article 33 under manufacture with its points 11. After some knitting rotations, the valve 31 is operated so as to feed compressed fluid into the annular chamber 20 and raise the piston 21. This latter raises the cup 27 by means of the rods 25 until it returns it to its initial maximum raised position, and the suction fan 35 is switched off.

The cycle described above may be repeated an indefinite number of times by moving the two mobile assemblies alternately relative to the main assembly 1 and auxiliary assembly 2 so as to give continuous tension during weaving of articles of any length. The auxiliary assembly 2 gives tension only for the time necessary for raising the piston 6.

Obviously the valves 15 and 31 are operated either automatically, for example by limit switches (not shown), or by control chain or control drum.

It can be seen that the device according to the invention ensures a continuous pulling action on articles under manufacture in an extremely rational manner and without limits of length, at the same time permitting the overall vertical size of circular knitting machines to be kept within normal limits.

Further it must be emphasized that the pairs of rods 7 and 25 with their corresponding connections always ensure rotation of the cup 27 and truncated conical body 10, and hence the points 28 and 11, in perfect synchronism with the rotation of the needle cylinders 4 and 5, so avoiding any twisting of the articles under manufacture 33. Obviously the device may be utilised for normal production by operating only the main assembly 1.

The invention so conceived is susceptible to numerous modifications all of which fall within the scope of the inventiveidea.

I claim:

l. A stretcher device for articles under manufacture on double cylinder circular knitting machines, comprising a first substantially vertical hydraulic cylinder fixed coaxially above the needle cylinders, a first piston slidingly mounted in said first hydraulic cylinder and rotatably supporting a first pair of vertical rods passing through corresponding passages formed in a body rigid with said needle cylinders and supporting at their lower ends first means of engagement with the articles under manufacture, said device being characterized in that it comprises a second hydraulic cylinder preferably coaxial with the first, a second piston slidably mounted in said second cylinder and provided with cavities for the slidable passage of said first pair of rods, a second pair of rods rotatably supported by said second piston and located in a substantially vertical direction a short distance one from the other, and passing into corresponding passages formed in said body rigid with the said needle cylinders and supporting at their lower ends second means of engagement with said articles under manufacture, said first and second hydraulic cylinders being operable independently and at different times for moving alternately in an upward or downward direction said first and second means of engagement with the articles under manufacture.

2. A device as claimed in claim 1, wherein said second means of engagement with the articles under manufacture comprise an inverted substantially cup like body provided with a plurality of projecting points at its lower edge, said cup like body being adapted to receive internally at least part of a substantially truncated conical body forming part of said first means of engagement and provided with a plurality of projecting points on its lower end at its edge.

3. A device as claimed in claim 2, wherein said truncated conical body is provided peripherally with a plurality of projections carrying the respective points. said projections. being able to slide in corresponding notches provided in the wall of said cup like body.

4. A device as claimed in claim 1, wherein said rods of said second pair of rods are fixed at their upper ends to a disc rotatably mounted on said second piston, said disc being provided with passages for said first pair of rods.

5. A device as claimed in claim. 1, wherein said second hydraulic cylinder comprises a substantially annular chamber in which said second annular piston slides in a tight manner, said annular chamber being limited inside by a tubular body for the passage of said pairs of rods.

6. A device as claimed in claim 1, wherein said disc is mounted on said second piston. by way of a rolling bearing.

7. A device as claimed in claim 1, wherein said second hydraulic cylinder is of the single effect type, bottom fed, the descent of said second piston being by gravity.

8. A device as claimed in claim 1, wherein said pairs of rods are disposed vertically, displaced about one with respect to the other.

9. A device as claimed in claim 1, wherein said second hydraulic cylinder is situated coaxially below said first hydraulic cylinder. 

1. A stretcher device for articles under manufacture on double cylinder circular knitting machines, comprising a first substantially vertical hydraulic cylinder fixed coaxially above the needle cylinders, a first piston slidingly mounted in said first hydraulic cylinder and rotatably supporting a first pair of vertical rods passing through corresponding passages formed in a body rigid with said needle cylinders and supporting at their lower ends first means of engagement with the articles under manufacture, said device being characterized in that it comprises a second hydraulic cylinder preferably coaxial with the first, a second piston slidably mounted in said second cylinder and provided with cavities for the slidable passage of said first pair of rods, a second pair of rods rotatably supported by said second piston and located in a substantially vertical direction a short distance one from the other, and passing into corresponding passages formed in said body rigid with the said needle cylinders and supporting at their lower ends second means of engagement with said articles undeR manufacture, said first and second hydraulic cylinders being operable independently and at different times for moving alternately in an upward or downward direction said first and second means of engagement with the articles under manufacture.
 2. A device as claimed in claim 1, wherein said second means of engagement with the articles under manufacture comprise an inverted substantially cup like body provided with a plurality of projecting points at its lower edge, said cup like body being adapted to receive internally at least part of a substantially truncated conical body forming part of said first means of engagement and provided with a plurality of projecting points on its lower end at its edge.
 3. A device as claimed in claim 2, wherein said truncated conical body is provided peripherally with a plurality of projections carrying the respective points, said projections being able to slide in corresponding notches provided in the wall of said cup like body.
 4. A device as claimed in claim 1, wherein said rods of said second pair of rods are fixed at their upper ends to a disc rotatably mounted on said second piston, said disc being provided with passages for said first pair of rods.
 5. A device as claimed in claim 1, wherein said second hydraulic cylinder comprises a substantially annular chamber in which said second annular piston slides in a tight manner, said annular chamber being limited inside by a tubular body for the passage of said pairs of rods.
 6. A device as claimed in claim 1, wherein said disc is mounted on said second piston by way of a rolling bearing.
 7. A device as claimed in claim 1, wherein said second hydraulic cylinder is of the single effect type, bottom fed, the descent of said second piston being by gravity.
 8. A device as claimed in claim 1, wherein said pairs of rods are disposed vertically, displaced about 90* one with respect to the other.
 9. A device as claimed in claim 1, wherein said second hydraulic cylinder is situated coaxially below said first hydraulic cylinder. 